Imaging systems and methods thereof

ABSTRACT

An imaging system includes a collimator assembly, a detector assembly and a control device. The collimator assembly is configured to collimate photons emitted from an imaged subject. The collimator assembly may include a plurality of slit-plates and a plurality of slats parallel to a transverse plane of the imaging system. Each of the plurality slit-plates may include one or more slits configured to collimate the photons in a first direction. The detector assembly is configured to generate signals based on the collimated photons. The control device is configured to place the plurality of slit-plates in a plurality of locations to provide a plurality of fields of view of the imaging system.

TECHNICAL FIELD

The present disclosure generally relates to imaging systems, and moreparticularly to collimation mechanisms for imaging systems, such as asingle photon emission tomography (SPECT) system.

BACKGROUND

Nuclear medicine tomographic imaging techniques, such as single photonemission tomography (SPECT), use electromagnetic radiation to produceimages of a patient. For example, the SPECT technique requiresadministration of a radionuclide to the patient. Gamma photons areemitted by the radionuclide as the radionuclide decays. The emittedgamma photons are detected to produce signals related to the patient(e.g., cross-sectional images). Multiple images can be acquired frommultiple angles to construct 3-D image data.

SUMMARY

In an aspect of the present disclosure, an imaging system is provided.The system may include a collimator assembly, a detector assembly, and acontrol device. The collimator assembly may be configured to collimatephotons emitted from an imaged subject. The collimator assembly mayfurther include a plurality of slit-plates and a plurality of slatsparallel to a transverse plane of the imaging system. In someembodiments, each of the plurality slit-plates may include one or moreslits configured to collimate the photons in a first direction. Thedetector assembly may be configured to generate signals based on thecollimated photons. The control device may be configured to place theplurality of slit-plates in a plurality of locations to provide aplurality of fields of view of the imaging system.

In some embodiments, the plurality of slit-plates and the plurality ofslats may be physically separated.

In some embodiments, the slit-plates may be curved plates includingmultiple axially oriented slits. In some embodiments, the one or moreslits may be perpendicular to the transverse plane of the imagingsystem.

In some embodiments, the plurality of slats may be placed between theslit-plates and the detector assembly for collimating the photons in asecond direction.

In some embodiments, the slats may be extended radially on a surface ofthe detector assembly.

In some embodiments, the plurality of fields of view may comprise afirst field of view corresponding to a first scanning mode for scanninga first body part and a second field of view corresponding to a secondscanning mode for scanning a second body part.

In some embodiments, the control device may be configured to move atleast one of the slit-plates from a first location to a second locationto switch between the first scanning mode and the second scanning mode.

In some embodiments, the control device may include an annular plateconnected to the at least one of the slit-plates.

In some embodiments, to control at least one of the slit-plates to bemoved from a first location to a second location, the control device maybe configured to control the annular plate to rotate around an axis ofthe annual plate from a first angle to a second angle.

In some embodiments, the plurality of slit-plates may include a firstnumber of slit-plates in a first segment in the axial direction and asecond number of slit-plates in a second segment in the axial direction.In some embodiments, the first number is different from the secondnumber.

In some embodiments, the axial direction may be perpendicular to thetransverse plane of the imaging system.

In some embodiments, the control device may include an actuating device.The control device may be configured to place the one or moreslit-plates in the plurality of locations to provide the plurality offields of view of the imaging system using the actuating device.

In some embodiments, the plurality of slit-plates may form a boreconfigured to accommodate the imaged subject. The system may furtherinclude a bore adjusting device configured to adjust the diameter of thebore.

In another aspect of the present disclosure, an imaging system isprovided. The system may include a collimator assembly, a detectorassembly, and one or more control devices. The collimator assembly mayinclude a plurality of slit-plates, each of the plurality slit-platesincluding one or more slits; and a plurality of slats defining a numberof channels between each two of the adjacent slats, the channelsarranged nonparallel to the one or more slits. The detector assembly maybe placed outside of the collimator assembly. The one or more controldevices may be configured to adjust relative positions between theslit-plates and the detector assembly to obtain an adjustable field ofview (FOV) surrounded by the slit-plates.

In some embodiments, the channels may be substantially perpendicular tothe slits.

In some embodiments, the slats may be arranged in fixed manner regardingto the detector assembly, and the slats may be configured to be placedat a plurality of location relative to the detector assembly.

In some embodiments, the one or more control devices may include twocontrol devices located at opposite ends of the detector assembly.

In a further aspect of the present disclosure, a method of adjustingcollimator assembly performance may be provided. The method may includemoving axially at least one of a plurality of slit-plates of acollimator assembly or one of a plurality of slats of the collimatorassembly to concurrently adjust a size of a field of view (FOV)surrounded by the collimator assembly; wherein a detector assembly maybe placed outside of the collimator assembly, wherein each of theplurality of slit-plates may include one or more slits; wherein theplurality of slats may define a number of channels between each two ofthe adjacent slats; and wherein the channels may be arrangednon-parallel to the one or more slits.

In some embodiments, moving axially at least one of the plurality ofslit-plates of the collimator assembly or one of the plurality of slatsof the collimator assembly may include rotating at least one of aplurality of slit-plates or one of a plurality of slats.

In some embodiments, the method may further include forming thecollimator assembly with at least one opening from the plurality ofslit-plates arranged in a ring configuration to form the opening.

Additional features will be set forth in part in the description whichfollows, and in part will become apparent to those skilled in the artupon examination of the following and the accompanying drawings or maybe learned by production or operation of the examples. The features ofthe present disclosure may be realized and attained by practice or useof various aspects of the methodologies, instrumentalities andcombinations set forth in the detailed examples discussed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is further described in terms of exemplaryembodiments. These exemplary embodiments are described in detail withreference to the drawings. These embodiments are non-limiting exemplaryembodiments, in which like reference numerals represent similarstructures throughout the several views of the drawings, and wherein:

FIG. 1 is a schematic diagram illustrating an exemplary imaging systemaccording to some embodiments of the present disclosure;

FIG. 2A is a schematic diagram illustrating an exemplary scanneraccording to some embodiments of the present disclosure;

FIG. 2B is a schematic diagram illustrating an exemplary computingdevice according to some embodiments of the present disclosure;

FIG. 3 is a schematic diagram illustrating exemplary hardware and/orsoftware components of an exemplary mobile device according to someembodiments of the present disclosure;

FIG. 4A is a schematic diagram illustrating an exemplary structure of acollimator assembly according to some embodiments of the presentdisclosure;

FIG. 4B is a schematic diagram illustrating an exemplary structure of acollimator assembly according to some embodiments of the presentdisclosure;

FIGS. 5A through 5D are schematic diagrams illustrating exemplary crosssections of slit-plates in different scanning modes according to someembodiments of the present disclosure;

FIG. 6 is a perspective view of an exemplary scanner according to someembodiments of the present disclosure;

FIGS. 7A through 7C are schematic diagrams illustrating cross-sectionalviews of an exemplary scanner in different scanning modes according tosome embodiments of the present disclosure; and

FIG. 8 is a schematic diagram illustrating a cross-sectional view of anexemplary scanner including a bore adjusting device according to someembodiments of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant disclosure. However, it should be apparent to those skilledin the art that the present disclosure may be practiced without suchdetails. In other instances, well-known methods, procedures, systems,components, and/or circuitry have been described at a relativelyhigh-level, without detail, in order to avoid unnecessarily obscuringaspects of the present disclosure. Various modifications to thedisclosed embodiments will be readily apparent to those skilled in theart, and the general principles defined herein may be applied to otherembodiments and applications without departing from the spirit and scopeof the present disclosure. Thus, the present disclosure is not limitedto the embodiments shown, but to be accorded the widest scope consistentwith the claims.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprise,”“comprises,” and/or “comprising,” “include,” “includes,” and/or“including,” when used in this specification, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof.

It will be understood that the term “system,” “engine,” “unit,”“module,” and/or “block” used herein are one method to distinguishdifferent components, elements, parts, section or assembly of differentlevel in ascending order. However, the terms may be displaced by otherexpression if they achieve the same purpose.

Generally, the word “module,” “unit,” or “block,” as used herein, refersto logic embodied in hardware or firmware, or to a collection ofsoftware instructions. A module, a unit, or a block described herein maybe implemented as software and/or hardware and may be stored in any typeof non-transitory computer-readable medium or any other storage device.In some embodiments, a software module/unit/block may be compiled andlinked into an executable program. It will be appreciated that softwaremodules can be callable from other modules/units/blocks or fromthemselves, and/or may be invoked in response to detected events orinterrupts. Software modules/units/blocks configured for execution oncomputing devices (e.g., processor 250 as illustrated in FIG. 2B) may beprovided on a computer-readable medium, such as a compact disc, adigital video disc, a flash drive, a magnetic disc, or any othertangible medium, or as a digital download (and can be originally storedin a compressed or installable format that needs installation,decompression, or decryption prior to execution). Such software code maybe stored, partially or fully, on a storage device of the executingcomputing device, for execution by the computing device. Softwareinstructions may be embedded in a firmware, such as an EPROM. It will befurther appreciated that hardware modules/units/blocks may be includedin connected logic components, such as gates and flip-flops, and/or canbe included of programmable units, such as programmable gate arrays orprocessors. The modules/units/blocks or computing device functionalitydescribed herein may be implemented as software modules/units/blocks,but may be represented in hardware or firmware. In general, themodules/units/blocks described herein refer to logicalmodules/units/blocks that may be combined with othermodules/units/blocks or divided into sub-modules/sub-units/sub-blocksdespite their physical organization or storage. The description may beapplicable to a system, an engine, or a portion thereof.

It will be understood that when a unit, engine, module or block isreferred to as being “on,” “connected to,” or “coupled to,” anotherunit, engine, module, or block, it may be directly on, connected orcoupled to, or communicate with the other unit, engine, module, orblock, or an intervening unit, engine, module, or block may be present,unless the context clearly indicates otherwise. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

These and other features, and characteristics of the present disclosure,as well as the methods of operation and functions of the relatedelements of structure and the combination of parts and economies ofmanufacture, may become more apparent upon consideration of thefollowing description with reference to the accompanying drawings, allof which form a part of this disclosure. It is to be expresslyunderstood, however, that the drawings are for the purpose ofillustration and description only and are not intended to limit thescope of the present disclosure. It is understood that the drawings arenot to scale.

Provided herein are systems and components for non-invasive imaging,such as for disease diagnosis or research purposes. In some embodiments,the imaging system may be a single photon emission computed tomography(SPECT) system. In some embodiments, the imaging system may be amulti-modality system, which combines a SPECT system with other types ofimaging systems including, for example, an emission computed tomography(ECT) system, a positron emission tomography (PET) system, or the like,or any combination thereof.

An imaging system, such as a SPECT system, may include a collimatorassembly that can filter a stream of photons to allow photons travellingin a particular direction to pass through. Imaging of different parts ofa patient (e.g., the head, the body, the heart) may require differentcollimator assemblies to achieve various fields of view (FOVs),sensitivity, and/or resolutions.

Conventional SPECT systems need a user to change another collimatorassembly manually when its FOV is changed. This may increase the user'sradiation exposure, as well as reduce efficiency in clinical diagnosis.In addition, conventional SPECT techniques used detector rings ofcircular cross sections to perform whole body imaging. The shape of thecross-section of a conventional detector ring is different from that ofa cross section of a patient. As such, the FOV of the conventionaldetector ring is not fully utilized in whole body imaging. Furthermore,conventional SPECT techniques used an FOV including only the heart forcardiac imaging, which may cause interior problems and reduce imagequality.

Aspects of the present disclosure address the above-mentioneddeficiencies by providing an imaging system that can automaticallyprovide desirable resolutions, sensitivity, and/or FOVs for variousscanning modes. The scanning modes may correspond to imaging of variousparts of a patient, such as the heart, the body, the head, etc. Theimaging system may include a collimator assembly configured to collimatephotons emitted from an imaged subject (e.g., a patient, a non-humanobject, etc.). The collimator assembly can include a plurality ofslit-plates and slates. The slit-plates can form one or more slits tocollimate the photons in a first direction. The slats may be configuredto collimate the photons in a second direction. In some embodiments, theslats may be positioned parallel to a transverse plane of the imagingsystem. The imaging system can also include a detector assembly fordetecting the photons. In some embodiments, a cross-section of thedetector assembly can be oval or elliptical.

FIG. 1 is a schematic diagram illustrating an exemplary imaging systemaccording to some embodiments of the present disclosure. In someembodiments, the imaging system 100 may be a SPECT system. As shown, theimaging system 100 may include a scanner 110, a network 120, one or moreterminals 130, a computing device 140, and a database 150.

The scanner 110 may include a gantry 111, a detector assembly 112, atable 113, and a collimator assembly (not shown). The gantry 111 maysupport the detector assembly 112 and the collimator assembly. An imagedsubject may be placed on the table 113 for SPECT scanning. Prior to theSPECT scanning, a radioisotope (e.g., a radiopharmaceutical substance)may be administered to the imaged subject. The radioisotope may emitphotons (e.g., gamma photons) during its decay process. The collimatorassembly may be located between the imaged subject and the detectorassembly 112 for collimating the photons emitted from the imagedsubject. The detector assembly 112 may detect the collimated photons andgenerate one or more signals based on the detected photons. The one ormore signals may include image data of the imaged subject.

In some embodiments, the scanner 110 may be a single-modality scanner,for example, a photon emission computed tomography (SPECT) scanner. Insome embodiments, the scanner 110 may be a multi-modality scanner, whichcombines a SPECT scanner with other types of scanners including, forexample, an emission computed tomography (ECT) scanner or a positronemission tomography (PET) scanners.

In some embodiments, a reference coordinate system 114 may beestablished. The reference coordinate system 114 may relate to SPECTscanning, data acquisition, image reconstruction, etc. In someembodiments, the longitudinal direction of the table 113 may be definedas the z-direction. A plane that is perpendicular to the z-direction(e.g., a transverse plane of a body part of an imaged subject) may bedefined as a x-y plane (also referred to as a transverse plane of theimaging system 100).

The network 120 may facilitate exchange of information and/or data forthe imaging system 100. In some embodiments, one or more components ofthe imaging system 100 (e.g., the scanner 110, the terminal 130, thecomputing device 140, the database 150, etc.) may communicateinformation and/or data with one or more other components of the SPECTsystem 100 via the network 120. For example, the computing device 140may obtain signals from the scanner 110 via the network 120. As anotherexample, the computing device 140 may obtain user instructions from theterminal 130 via the network 120. The network 120 may be and/or includea public network (e.g., the Internet), a private network (e.g., a localarea network (LAN), a wide area network (WAN)), etc.), a wired network(e.g., an Ethernet network), a wireless network (e.g., an 802.11network, a Wi-Fi network, etc.), a cellular network (e.g., a Long TermEvolution (LTE) network), a frame relay network, a virtual privatenetwork (“VPN”), a satellite network, a telephone network, routers,hubs, switches, server computers, and/or any combination thereof. Merelyby way of example, the network 120 may include a cable network, awireline network, a fiber-optic network, a telecommunications network,an intranet, a wireless local area network (WLAN), a metropolitan areanetwork (MAN), a public telephone switched network (PSTN), a Bluetooth™network, a ZigBee™ network, a near field communication (NFC) network, orthe like, or any combination thereof. In some embodiments, the network120 may include one or more network access points. For example, thenetwork 120 may include wired and/or wireless network access points suchas base stations and/or internet exchange points through which one ormore components of the imaging system 100 may be connected to thenetwork 120 to exchange data and/or information.

The terminal(s) 130 may communicate with the scanner 110, and/or thecomputing device 140. For example, a user may set a scanning parameterfor the scanner 110 via the terminal(s) 130. As another example, theterminal(s) 130 may acquire a SPECT image from the computing device 140.The terminal(s) 130 may include a mobile device 131, a tablet computer132, a laptop computer 133, or the like, or any combination thereof. Insome embodiments, the mobile device 131 may include a smart home device,a wearable device, a mobile device, a virtual reality device, anaugmented reality device, or the like, or any combination thereof. Insome embodiments, the smart home device may include a smart lightingdevice, a control device of an intelligent electrical apparatus, a smartmonitoring device, a smart television, a smart video camera, aninterphone, or the like, or any combination thereof. In someembodiments, the wearable device may include a bracelet, a footgear,eyeglasses, a helmet, a watch, clothing, a backpack, a smart accessory,or the like, or any combination thereof. In some embodiments, the mobiledevice may include a mobile phone, a personal digital assistance (PDA),a gaming device, a navigation device, a point of sale (POS) device, alaptop, a tablet computer, a desktop, or the like, or any combinationthereof. In some embodiments, the virtual reality device and/or theaugmented reality device may include a virtual reality helmet, virtualreality glasses, a virtual reality patch, an augmented reality helmet,augmented reality glasses, an augmented reality patch, or the like, orany combination thereof. For example, the virtual reality device and/orthe augmented reality device may include a Google Glass™, an OculusRift™, a Hololens™, a Gear VR™, etc. In some embodiments, theterminal(s) 130 may be part of the computing device 140.

The computing device 140 may process data and/or information obtainedfrom the scanner 110, the terminal 130, and/or the database 150. Forexample, the computing device 140 may process signals obtained from thescanner 110 and reconstruct a SPECT image. In some embodiments, thecomputing device 140 may be a computer, a user console, a single serveror a server group, etc. The server group may be centralized ordistributed. In some embodiments, the computing device 140 may be localor remote. For example, the computing device 140 may access informationand/or data stored in the scanner 110, the terminal 130, and/or thedatabase 150 via the network 120. As another example, the computingdevice 140 may be directly connected to the scanner 110, the terminal130 and/or the database 150 to access stored information and/or data. Insome embodiments, the computing device 140 may be implemented on a cloudplatform. Merely by way of example, the cloud platform may include aprivate cloud, a public cloud, a hybrid cloud, a community cloud, adistributed cloud, an inter-cloud, a multi-cloud, or the like, or anycombination thereof.

The database 150 may store data, instructions, and/or any otherinformation. In some embodiments, the database 150 may store dataobtained from the terminal 130 and/or the computing device 140. In someembodiments, the database 150 may store data and/or instructions thatthe computing device 140 may execute or use to perform exemplary methodsdescribed in the present disclosure. In some embodiments, the database150 may include a mass storage, a removable storage, a volatileread-and-write memory, a read-only memory (ROM), or the like, or anycombination thereof. Exemplary mass storage may include a magnetic disk,an optical disk, a solid-state drive, etc. Exemplary removable storagemay include a flash drive, a floppy disk, an optical disk, a memorycard, a zip disk, a magnetic tape, etc. Exemplary volatileread-and-write memory may include a random access memory (RAM).Exemplary RAM may include a dynamic RAM (DRAM), a double date ratesynchronous dynamic RAM (DDR SDRAM), a static RAM (SRAM), a thyristorRAM (T-RAM), and a zero-capacitor RAM (Z-RAM), etc. Exemplary ROM mayinclude a mask ROM (MROM), a programmable ROM (PROM), an erasableprogrammable ROM (EPROM), an electrically erasable programmable ROM(EEPROM), a compact disk ROM (CD-ROM), and a digital versatile disk ROM,etc. In some embodiments, the database 150 may be implemented on a cloudplatform. Merely by way of example, the cloud platform may include aprivate cloud, a public cloud, a hybrid cloud, a community cloud, adistributed cloud, an inter-cloud, a multi-cloud, or the like, or anycombination thereof.

In some embodiments, the database 150 may be connected to the network120 to communicate with one or more other components in the imagingsystem 100 (e.g., the computing device 140, the terminal 130, etc.). Oneor more components in the imaging system 100 may access the data orinstructions stored in the database 150 via the network 120. In someembodiments, the database 150 may be directly connected to orcommunicate with one or more other components in the image system 100(e.g., the computing device 140, the terminal 130, etc.). In someembodiments, the database 150 may be part of the computing device 140.

FIG. 2A is a schematic diagram illustrating an exemplary scanneraccording to some embodiments of the present disclosure. As illustratedin FIG. 2A, the scanner 110 may include a collimator assembly 210, adetector assembly 220 and a control device 230.

The collimator assembly 210 may collimate photons emitted from an imagedsubject. The collimator assembly 210 may be placed between an imagedsubject and the detector assembly 220 for surrounding the imaged subjectand collimating photons from the imaged subject. In some embodiments,the collimator assembly 210 may include a plurality of sections. Theplurality of sections may be configured as a flexible shape, forexample, a bore. The shape, size, and/or location of the flexible shapemay be adjustable. In some embodiments, the plurality of the sectionsmay be coupled to the control device 230, and the shape, size, and/orlocation of the flexible shape may be adjusted by the control device230. In some embodiments, each of the plurality of sections may includea plurality of openings. Photons from a field of view may pass throughthe plurality of opening and reach the detector assembly 220. Merely forillustration purposes, the plurality of openings may be holes (e.g.,parallel holes, divergent holes, convergent holes, a pinhole, etc.),gaps, etc. The collimator assembly 210 may collimate photons in certaindirections using the plurality of opening.

In some embodiments, the collimator assembly 210 may include a pluralityof slit-plates. The slit-plates may be movable relative to the detectorassembly 220. In some embodiments, the slit-plates may be configured asa flexible shape. The slit-plates may further include one or more slits.In some embodiments, the slit-plates may be curved plates includingmultiple axially oriented slits. The slits may be grooves with certainlengths and widths. The slits may collimate photons in certaindirections. In some embodiments, the collimator assembly 210 may furtherinclude a plurality of slats. The slats may be placed between theslit-plates and the detector assembly 220. In some embodiments, theslats may collimate photons in another direction (e.g., a directionperpendicular to the direction of the slit). In some embodiments, theslit-plates and the slats are physically separated.

The detector assembly 220 may detect photons from a FOV. The detectorassembly 220 may be placed behind the collimator assembly 210 to detectcollimated photons. The detector assembly 220 may generate one or moresignals based on the detected photons. In some embodiments, the one ormore signals may be transmitted to a computing device, for example, thecomputing device 140, to reconstruct an image.

In some embodiments, the detector assembly 220 may include one or moredetector units. The detector units may include a scintillator, a lightsensitive element (e.g., photomultiplier tube, photodiodes, optoelectrictransducer, etc.), semiconductor crystals, or the like, or a combinationthereof. In some embodiments, the detector assembly 220 may have aplurality of sizes or shapes. Merely by ways of example, thecross-section of the detector assembly 220 may be an arc, an oval, acircle, a polygon, etc. In some embodiments, the detector assembly 220may be an oval-shaped detector. In some embodiments, the detectorassembly 220 may be stationary relative to the reference coordinatesystem 114.

The control device 230 may perform particular functions relate to ascanning of a body part of an imaged subject. In some embodiments, thecontrol device 230 may drive the table 113 to move in the z-direction.During the moving process, the detector assembly 220 may detect photonsfrom a body part of the imaged subject and generate signals based on thedetected photons.

In some embodiments, the control device 230 may place the slit-plates ofthe collimator assembly 210 in a plurality of locations. At differentlocations, the detector assembly 220 may detect photons from differentFOVs. For example, the control device 230 may include a mechanicaldevice. The mechanical device may connect to one or more slit-plates ofthe collimator assembly 210. The control device 230 may drive the one ormore slit-plates to different locations by moving the mechanical devicein certain directions (e.g., a direction in the z-direction) to achievedesirable resolutions, sensitivity, and/or FOVs.

It should be noted that the above description of the scanner 110 ismerely provided for the purposes of illustration, and not intended tolimit the scope of the present disclosure. For persons having ordinaryskills in the art, multiple variations and modifications may be madeunder the teachings of the present disclosure. For example, the assemblyand/or function of the scanner 110 may be varied or changed according tospecific implementation scenarios. As another example, the scanner 110may further include a patient positioning system for adjusting theposition of an imaged subject relative to the table 113. However, thosevariations and modifications do not depart from the scope of the presentdisclosure.

FIG. 2B is a schematic diagram illustrating an exemplary computingdevice according to some embodiments of the present disclosure. Asillustrated in FIG. 2B, the computing device 140 may include a processor250, a storage 260, an input/output (I/O) 270, and a communication port280.

The processor 250 may execute computer instructions (e.g., program code)and perform functions of the computing device 140 in accordance withtechniques described herein. The computer instructions may include, forexample, routines, programs, objects, components, data structures,procedures, modules, and functions, which perform particular functionsdescribed herein. For example, the processor 250 may perform imagereconstruction operations to reconstruct a SPECT image based on lone ormore signals. The one or more signals may be obtained from the scanner110, the terminal 130, the database 150, and/or any other component ofthe imaging system 100. In some embodiments, the processor 250 mayreconstruct the SPECT image based on one or more algorithms, such asfiltered back projection, inverse matrix, etc.

In some embodiments, the processor 250 may include one or more hardwareprocessors, such as a microcontroller, a microprocessor, a reducedinstruction set computer (RISC), an application specific integratedcircuits (ASICs), an application-specific instruction-set processor(ASIP), a central processing unit (CPU), a graphics processing unit(GPU), a physics processing unit (PPU), a microcontroller unit, adigital signal processor (DSP), a field programmable gate array (FPGA),an advanced RISC machine (ARM), a programmable logic device (PLD), anycircuit or processor capable of executing one or more functions, or thelike, or any combinations thereof.

Merely for illustration, only one processor is described in thecomputing device 140. However, it should be noted that the computingdevice 140 in the present disclosure may also include multipleprocessors, thus operations and/or method steps that are performed byone processor as described in the present disclosure may also be jointlyor separately performed by the multiple processors.

The storage 260 may store data/information obtained from the scanner110, the terminal 130, the database 150, and/or any other component ofthe imaging system 100. In some embodiments, the storage 260 may includea mass storage, a removable storage, a volatile read-and-write memory, aread-only memory (ROM), or the like, or any combination thereof. Forexample, the mass storage may include a magnetic disk, an optical disk,a solid-state drive, etc. The removable storage may include a flashdrive, a floppy disk, an optical disk, a memory card, a zip disk, amagnetic tape, etc. The volatile read-and-write memory may include arandom access memory (RAM). The RAM may include a dynamic RAM (DRAM), adouble date rate synchronous dynamic RAM (DDR SDRAM), a static RAM(SRAM), a thyristor RAM (T-RAM), and a zero-capacitor RAM (Z-RAM), etc.The ROM may include a mask ROM (MROM), a programmable ROM (PROM), anerasable programmable ROM (EPROM), an electrically erasable programmableROM (EEPROM), a compact disk ROM (CD-ROM), and a digital versatile diskROM, etc. In some embodiments, the storage 260 may store one or moreprograms and/or instructions to perform exemplary methods described inthe present disclosure. For example, the storage 260 may store a programfor the computing device 140 for reconstructing a SPECT image based onimage obtained from the scanner 110.

The I/O 270 may input and/or output signals, data, information, etc. Insome embodiments, the I/O 270 may enable a user interaction with thecomputing device 140. In some embodiments, the I/O 270 may include aninput device and an output device. Examples of the input device mayinclude a keyboard, a mouse, a touch screen, a microphone, or the like,or a combination thereof. Examples of the output device may include adisplay device, a loudspeaker, a printer, a projector, or the like, or acombination thereof. Examples of the display device may include a liquidcrystal display (LCD), a light-emitting diode (LED)-based display, aflat panel display, a curved screen, a television device, a cathode raytube (CRT), a touch screen, or the like, or a combination thereof.

The communication port 280 may be connected to a network (e.g., thenetwork 120) to facilitate data communications. The communication port280 may establish connections between the computing device 140 and thescanner 110, the terminal 130, and/or the database 150. The connectionmay be a wired connection, a wireless connection, any othercommunication connection that can enable data transmission and/orreception, and/or any combination of these connections. The wiredconnection may include, for example, an electrical cable, an opticalcable, a telephone wire, or the like, or any combination thereof. Thewireless connection may include, for example, a Bluetooth™ link, aWi-Fi™ link, a WiMax™ link, a WLAN link, a ZigBee link, a mobile networklink (e.g., 3G, 4G, 5G, etc.), or the like, or a combination thereof. Insome embodiments, the communication port 280 may be and/or include astandardized communication port, such as RS232, RS485, etc. In someembodiments, the communication port 280 may be a specially designedcommunication port. For example, the communication port 280 may bedesigned in accordance with the digital imaging and communications inmedicine (DICOM) protocol.

FIG. 3 is a schematic diagram illustrating exemplary hardware and/orsoftware components of an exemplary mobile device 300 on which theterminal 130 may be implemented according to some embodiments of thepresent disclosure. As illustrated in FIG. 3, the mobile device 300 mayinclude a communication platform 310, a display 320, a graphicprocessing unit (GPU) 330, a central processing unit (CPU) 340, an I/O350, a memory 360, and a storage 390. In some embodiments, any othersuitable component, including but not limited to a system bus or acontroller (not shown), may also be included in the mobile device 300.In some embodiments, a mobile operating system 370 (e.g., iOS™,Android™, Windows Phone™, etc.) and one or more applications 380 may beloaded into the memory 360 from the storage 390 in order to be executedby the CPU 340. The applications 380 may include a browser or any othersuitable mobile apps for receiving and rendering information relating toimage reconstruction or other information from the computing device 140.User interactions with the information stream may be achieved via theI/O 350 and provided to the computing device 140 and/or other componentsof the imaging system 100 via the network 120.

To implement various modules, units, and their functionalities describedin the present disclosure, computer hardware platforms may be used asthe hardware platform(s) for one or more of the elements describedherein. A computer with user interface elements may be used to implementa personal computer (PC) or any other type of work station or terminaldevice. A computer may also act as a server if appropriately programmed.

FIG. 4A is a schematic diagram illustrating an exemplary structure of acollimator according to some embodiments of the present disclosure. Thestructure 400 may be provided for illustration purposes, in someembodiments, the structure 400 may be a part of a collimator assembly,which may be configured as a flat plate or a curved plate. The structure400 may include a slit-plate 401 and a plurality of slats 403.

The slit-plate 401 may include a slit 402. The slit 402 may be anopening through which photons may pass. As illustrated in FIG. 4A, theslit 402 may be aligned with the z-direction of the reference coordinatesystem 114 (i.e., the slit is perpendicular to the transvers plane ofthe imaging system 100). The slit 402 may collimate photons in thez-direction. The slit 402 may have a certain width. The width of theslit 402 may relate to spatial resolution and photon sensitivity of theimaging system 100. In some embodiments, the width of the slit 402 maybe determined according to default settings or certain requirements ofthe imaging system 100. In some embodiments, the slit 402 may have othershapes. For example, the slit 402 may be a curve, a wavy line, a brokenline, etc.

The plurality of slats 403 may be positioned between the slit-plate 401and the detector assembly 404. In some embodiments, the plurality ofslats 403 may be fixed or extended radially on a surface of the detectorassembly 404. The plurality of slats 403 may be configured as evenlydistributed strips that form a plurality of openings. Photons may passthrough the openings and reach the detector assembly 404. The width ofthe opening may also relate to spatial resolution and photon sensitivityof the imaging system 100. In some embodiments, the width of the openingmay be adjusted by increasing/decreasing the number of the slats 403according to default settings or certain requirements of the imagingsystem 100. The direction of the plurality of slats 403 may beperpendicular to the slit 402. Thus the slats 403 may be positioned inthe x-direction of the reference coordinate system 114 for collimatingphotons in the x-direction. In some embodiments, the plurality of slats403 may be positioned in the y-direction, or any other direction alongthe x-y plane of the reference coordinate system 114 for collimatingphotons in the corresponding direction. The plurality of slats 403 maydefine a number of channels between each two of the adjacent slats, thechannels arranged nonparallel to the slit 402.

In some embodiments, the slit-plate may include one or more parts. Theone or more parts may refer to different segments of the slit-plate inthe z-direction. In some embodiments, the number and/or the positions ofthe slits included in one or more parts of a slit-plate may bedifferent. For example, a first part of the slit-plate corresponding toa range from z=0˜10 in the reference coordinate system 114 may includetwenty slits. A second part of the slit-plate from z=10˜20 may includeone hundred slits.

It should be noted that the above description of the structure 400 ismerely provided for the purposes of illustration, and not intended tolimit the scope of the present disclosure. For persons having ordinaryskills in the art, multiple variations and modifications may be madeunder the teachings of the present disclosure. For example, theslit-plate 401 may not be parallel to the detector assembly 404 asillustrated in FIG. 4A. However, those variations and modifications donot depart from the scope of the present disclosure.

FIG. 4B is a schematic diagram illustrating an exemplary structure of acollimator assembly according to some embodiments of the presentdisclosure. The structure 450 may include a slit-plate 451, and aplurality of slats 453. The slit-plate 451 may also include a slit 452thereon. In some embodiments, the slit-plate 451 may be parallel to thedetector assembly 454. FIG. 4B illustrates a similar collimator assemblystructure as described with reference to FIG. 4A except that the slit452 on the slit-plate 451 may be set in a direction different from thedirection in which slit 402 be set. In some embodiments, slit 452 may bein any-direction except the direction perpendicular to the z-direction.

FIGS. 5A through 5D are schematic diagrams illustrating exemplary crosssections of slit-plates in different scanning modes according to someembodiments of the present disclosure. The imaging system 100 mayimplement a plurality of scanning modes. In some embodiments, theplurality of scanning modes may be used for scanning different bodyparts of an imaged subject. For example, the scanning modes may includea first scanning mode, a second scanning mode, a third scanning mode,etc. The first scanning mode, the second scanning mode, and the thirdscanning mode may correspond to scanning of a first body part, a secondbody part, and a third body part, respectively. The first scanning mode,the second scanning mode, and the third scanning mode may correspond toa first FOV, a second FOV, and a third FOV, respectively. The first FOV,the second FOV, and the third FOV may or may not be the same. Merely forillustration purposes, a head scanning mode may be used for scanning thehead of a patient; a whole-body scanning mode may be used for scanningthe whole body of a patient; and a heart scanning mode may be used forscanning the heart of a patient. In some embodiments, each of theplurality of the scanning modes may have different scanning parameters,for example, FOV, spatial resolution, sensitivity, or the like, or acombination thereof. For example, a whole-body scanning mode may need alarger FOV than a head scanning mode and a heart scanning mode. Asanother example, the heart scanning mode may need a larger sensitivitythan the whole-body scanning mode and the head scanning mode.

Referring to FIG. 5A, a cross section of the slit-plates of a collimatorassembly in the head scanning mode may be illustrated. The collimatorassembly 500 may include a plurality of (e.g., four) slit-plates and aplurality of slats (not shown). Each of the plurality of slit-plates mayinclude one or more slits. The detector assembly 505, behind thecollimator assembly 500, may be stationary relative to the referencecoordinate system 114. In some embodiments, the cross section of thedetector assembly 505 may be oval. The detector assembly 505 may detectphotons from a FOV 503, and generate signals based on the detectedphotons.

In some embodiments, in the head scanning mode, the FOV 503 may becircular. In some embodiments, the FOV 503 may be centered on the axisof the detector assembly 505. The FOV 503 may have a plurality of sizes.In some embodiments, the size of the FOV 503 may relate to the size ofthe head of patients. For example, the FOV 503 may be larger for adults,and may be smaller for kids. The shape, location, and/or size of the FOV503 may be set by a user (e.g., a doctor), according to a defaultsetting of the imaging system 100, etc. In some embodiments, the scanner110 may further include a patient positioning device for placing animaged body part to a predetermined location. For example, the patientpositioning unit may place the head of a patient in the FOV 503.

The slit-plates may be positioned at certain locations during the headscanning mode. In some embodiments, the locations of the slit-plates maybe predetermined by a user, or according to a default setting of theimaging system 100, or a combination of both. In some embodiments, thelocation of slit-plates may be determined according to one or morescanning parameters including, for example, FOV, spatial resolution,and/or sensitivity. In the head scanning mode, the locations ofslit-plates may be determined according to the resolution and/or FOV theof the imaging system 100. The resolution may relate to the distancebetween the slits on the plurality of slit-plates and the detectorassembly 505. For example, a longer distance between the slits and thedetector assembly 505 may lead to a higher resolution.

In some embodiments, in the head scanning mode, the plurality ofslit-plates may be positioned at certain locations to encompass the FOV503. In some embodiments, the shape formed by the slit-plates may becircular. As illustrated in FIG. 5A, the four slit-plates may roughlyform a circle encompassing the FOV 503.

In some embodiments, the number of slits used in the head scanning modemay depend on the FOV and the locations of the slit-plates. In the x-yplane, the slits may function as one-dimensional pinholes. Photons fromthe FOV 503 may pass through the slits, and form a plurality ofprojections on the detector assembly 505. The detector assembly 505 maygenerate signals based on the projections. Taking a slit 502 on aslit-plate 501 as an example, photons that pass through the slit 502 mayform a projection 504 on detector assembly 505. In some embodiments, theslits may be set according to the projections on the detector assembly505. For example, a proper number of slits be determined when thedetector 505 assembly has accommodated a largest number of projections.

Referring to FIG. 5B, a cross section of the slit-plates of a collimatorassembly in the whole-body scanning mode may be illustrated. In someembodiments, the collimator assembly 520 and the detector assembly 525may be similar to or same as those in FIG. 5A.

In the whole-body scanning mode, the FOV 523 may be oval. And the FOV523 may be centered on the axis of the detector assembly 525. In someembodiments, the size of the FOV 523 may be set to accommodate the wholebody of an imaged subject. In some embodiments, the shape, location,and/or size, of the FOV 523 may be set by a user, according to a defaultsetting of the imaging system 100, etc.

The slit-plates may be positioned at certain locations during thewhole-body scanning mode. The location of a slit-plate may be determinedbased on one or more scanning parameters including, for example, FOV,spatial resolution, sensitivity, etc. In some embodiments, the locationsof the slit-plates may be determined according to the FOV. Theslit-plates may be positioned at certain locations to encompass the FOV523. In some embodiments, the shape formed by the slit-plates may beoval. As illustrated in FIG. 5B, the four slit-plates may connect toeach other with end to end, to form an oval encompassing the FOV 523.

The number of slits used in the whole-body scanning mode may be the sameas or more than that in the head scanning mode. In some embodiments, theslit-plates or a part of it used in the whole-body scanning mode may bethe same as those used in the head scanning mode.

Referring to FIG. 5C, a cross section of the slit-plates of a collimatorassembly in the heart scanning mode may be illustrated. In someembodiments, the detector assembly 545 and the slats of the collimatorassembly 540 (not shown) may be similar to or same as the embodimentsshown in FIG. 5A.

In the heart scanning mode, the FOV 543 may be circular foraccommodating scanning of the heart of a patient. The position of theFOV 543 relative to the axis of the detector assembly 545 may bedetermined according to the off-center location of the heart of apatient. In some embodiments, the shape, location, and/or size, of theFOV 543 may be set by a user, according to a default setting of theimaging system 100, etc.

The slit-plates may be positioned at certain locations during the heartscanning mode. In some embodiments, the locations of the slit-plates ofthe collimator assembly 540 may be the same as the embodiments shown inFIG. 5B.

In some embodiments, the number of slits used in the heart scanning modemay depend on the FOV and sensitivity. The sensitivity may relate to thenumber of slits used in the scanning process. For example, a largernumber of slits may correspond to a higher sensitivity. In someembodiments, the number of slits used in the heart scanning mode may bemore than that used in the head scanning mode and the whole-bodyscanning mode.

Referring to FIG. 5D, a cross section of the slit-plates of a collimatorassembly in the heart scanning mode may be illustrated. In someembodiments, the embodiment described in FIG. 5D may be same as orsimilar to the descriptions with reference to FIG. 5C except than thedetector assembly 563 may detect photons from two FOVs including a firstFOV 561 and a second FOV 562. In some embodiments, the first FOV 561 maycorrespond to the heart of the patient. The second FOV 562 maycorrespond to the whole body of the patient.

The detector assembly 563 may include a plurality of detector units. Thedetector units may be positioned along the circumferential direction ofthe detector assembly 563 in x-y plane. In some embodiments, the photonsfrom the first FOV 561 may be detected by a first set of detector unitsof the detector assembly 563, and the photons from the second FOV 562may be detected by a second set of detector units of the detectorassembly 563. In some embodiments, the detector units that is closer tothe center of the FOV 561 (e.g., than a threshold distance set by auser) may be determined as the first set of detector units.

The detector assembly 563 may generate signals based on photons from thefirst FOV 561 and the second FOV 562. The signals may be transmitted toa computing device, for example, the computing device 140, to generatean image of the heart of a patient.

In some embodiments, the collimator assemblies and the detectorassemblies illustrated in FIG. 5A through 5D may be implemented by asame scanner. In different scanning modes including head scanning mode,whole-body scanning mode, and heart scanning mode, the slit-plates ofthe collimator assembly may be placed in a plurality of locations. Thusthe detector assembly may detect photons from different FOVs, andgenerate signals accordingly.

For example, with reference to FIG. 5A and FIG. 5B, the imaging system100 may be in a head scanning mode and a whole-body scanning moderespectively. The imaging system 100 may switch between the headscanning mode and the whole-body scanning mode by switching the FOVbetween a first FOV corresponding to the head of a patient and a secondFOV corresponding to the whole body of the patient. In some embodiments,the FOV may be switched between the first FOV and the second FOV bydriving the four slit-plates in radial directions in the x-y plane tothe locations shown in FIG. 5A and FIG. 5B.

As another example, with reference to FIG. 5B and FIG. 5C, the imagingsystem 100 may be in a whole-body scanning mode and a heart scanningmode respectively. The imaging system 100 may switch between thewhole-body scanning mode and the heart scanning mode by switching theFOV between a second FOV corresponding to the whole body of a patientand a third FOV corresponding to the heart of the patient. In someembodiments, the FOV may be switched between the second FOV and thethird FOV by driving the four slit-plates in the z-direction to placeanother part of the slits-plates, which may include a different numberof slits, above the detector assembly. In some embodiments, the switchbetween different scanning modes may be implemented by a control deviceas described elsewhere in the present disclosure (e.g., FIG. 6 throughFIG. 8, and the descriptions thereof).

FIG. 6 is a perspective view of an exemplary scanner according to someembodiments of the present disclosure. The scanner 600 may include acollimator assembly 601, a detector assembly 602, and a control device603. The collimator assembly 601 may include a plurality of slit-platesand a plurality of slats (not shown). The plurality of slit-plates isconfigured as a flexible shape (e.g., a bore) surrounding an imagedsubject. The slates may be positioned on a surface of the detectorassembly 602. The detector assembly 602 may detect photons emitted froma FOV. In some embodiments, the detector assembly 602 may be stationaryrelative to the reference coordinate system 114. The cross section ofthe detector assembly 602 may be oval.

The control device 603 may be configured to drive the slit-plates to aplurality of locations. For example, the control device 603 may beconfigured to control at least one of the slit-plates to be moved from afirst location to a second location to switch between different scanningmodes and provide a plurality of fields of view. The plurality of fieldsof view includes a first field of view corresponding to a first scanningmode for scanning a first body part and a second field of viewcorresponding to a second scanning mode for scanning a second body part.

The control device 603 may include two shape-control devices 604 and605. The two shape-control devices 604 and 604 may be positioned in x-yplanes (also referred to as a transverse planes of the imaging system100). In some embodiment, each of the shape-control devices 604 and 605may include an annular plate. The annular plates may have larger innerdiameters than the diameter of the shape formed by the slit-plates ofthe collimator assembly 601 in x-y planes. The detector assembly 602 maybe positioned between the two annular plates. In some embodiments, thelength of the slit-plates in the z-direction may substantially equal tothe distance between the two annular plates.

In some embodiments, each of the shape-control devices 604 and 605 mayinclude a plurality of guide rails and a plurality of sliders. Theplurality of guide rails may be fixed on the surface of the annularplates or embedded in the annular plates. In some embodiments, the guiderails may be grooves in the annular plates. The plurality of guide railsmay be evenly distributed on the annular plates of the shape-controldevices 604 and 605. For example, the guide rails may evenly distributedalong the circumferential direction of the annular plates of the controldevices 604 and 605. In some embodiments, the guide rails may have aplurality of shapes or sizes. For example, the guide rails may be anarc, a straight line, etc.

Each of the plurality of slider may slide in a guide rail. Merely forillustration purposes, the slider may be a ball, a block, a wheel, orthe like, or a combination thereof. In some embodiments, each of theplurality of sliders may be connected to a slit-plate of the collimatorassembly 601 through a connector, for example, a rod, a chain, a lever,or the like. As illustrated in FIG. 6, a slider 605 may slide in a guiderail 606. The guide rail 606 may be a groove on the annular plates ofthe shape-control device 604. The slider 607 may be connected to aslit-plate 609 through a rigid rod 608.

Thus the annular plates may connected to the at least one of theslit-plates, for example, through the guide rails, sliders, and/or aconnector. The slit-plate 609 may be driven to a plurality of locationsby moving of the annular plates of the shape-control devices 604 and605. For example, when the annular plates of the shape-control devices604 and 605 are driven to do axial rotation in x-y plane (e.g., from afirst angle to a second angle), a stress may be applied to the slider607 due to the moving of the guide rail 606 along with the annularplates of the shape-control device 604. The slider 607 may be driven toslide in the guide rail 606, and the slit-plate 609 may be moved to apredetermined location (e.g., the location as illustrated in FIG. 5A orFIG. 5B). As another example, when the shape-control devices 604 and 605are driven to move in the z-direction, the collimator assembly 601 aswell as the slit-plates may be moved to a plurality of locations. Thedetector assembly 602 may be stationary relative to the referencecoordinate system 114. Thus the relative position of the slit-plates tothe detector assembly 602 may be changed. For example, a certain part ofthe slit-plates with a larger number of slits may be positioned abovethe detector assembly 602.

In some embodiments, the control device 603 may further include aplurality of bore adjusting devices. The bore adjusting devices mayfacilitate the adjustment of the diameter of the bore of the scanner600. The bore of a scanner may refer to the space within which a patientmay be positioned. In some embodiments, the diameter of the bore may bereferred to as the diameter of the opening space form by the slit-platesof the collimator assembly 601. The bore adjusting devices may be usedto adjust of the diameter of the bore by driving the slit-plates tocertain locations. For example, the bore adjusting devices may be usedto increase the diameter of the bore by driving the slit-plates tofarther locations relative to the center of the bore. The slit-platesmay be driven, in radial directions in x-y plane (also referred to as atransverse plane of the imaging system 100), to farther locations.Merely for illustration purposes, a bore adjusting device 610 isdescribed. The bore adjusting device 610 may be a rigid structure. Therigid structure may be connected to the slit-plates through one or morejoints. In some embodiments, the slit-plates may be driven to aplurality of locations in radial directions relative to the center ofthe bore in x-y plane through the bore adjusting devices.

The control device 603 may also include a plurality of actuating devices(not shown) for actuating the shape-control devices and/or the boreadjusting devices. The actuating device may be any device that iscapable of providing a force to drive the shape-control devices (e.g.,to do axial rotation or to move to a certain location in thez-direction) and/or the bore adjusting devices (e.g., to move in radialdirection in x-y plane). Merely by ways of example, the actuating deviceincludes a hydraulic actuator, a pneumatic actuator, an electricactuator (e.g., an electrical motor), a thermal actuator, a magneticactuator, a mechanical actuator, or the like, or a combination thereof.

FIGS. 7A through 7C are schematic diagrams illustrating cross-sectionalviews of an exemplary scanner in different scanning modes according tosome embodiments of the present disclosure. Referring to FIG. 7A, across section of the scanner 700 in the head scanning mode may beillustrated. The scanner 700 may include a collimator assembly 701, adetector assembly 702, and a control device 703. The collimator assembly701 may include four slit-plates, which may form a flexible shape. Inthe head scanning mode, the FOV of the imaging system 100 may becircular and the four slit-plates of the collimator assembly 701 may beconfigured to form a circular shape as described with reference to FIG.5A. The detector assembly 702, which is located behind the collimatorassembly 701, may be stationary relative to the reference coordinatesystem 114. In some embodiments, the cross section of the detectorassembly 702 may be oval.

The control device 703 may include a plurality of shape-control devices704. The shape-control devices 704 may include annual plates on which aplurality of guide rails may be embedded. In some embodiments, the guiderails may be arc-shaped grooves evenly embedded in the annual plates ofthe shape-control devices 704 along its circumferential direction.Taking a guide rail 705 as an example, a slider 706 may slide in theguide rail 705. In some embodiments, the slider 706 may be located atthe bottom 707 of the guide rail 705 in the head scanning mode. Theslider 706 may be connected to a slit-plate 709 through a rigid plate710.

The control device 703 may include an actuating device (not shown) suchas an electrical motor. The actuating device may drive the annual platesof the shape-control devices 704 to do axial rotation in x-y plane. Insome embodiments, the shape formed by the slit-plates of the collimatorassembly 701 may be flexibly adjusted, and the scanner 700 may switchbetween the head scanning mode and the whole-body scanning mode byrotating the shape-control devices 704.

In some embodiments, the annual plates of the shape-control devices 704may rotate in clockwise. A stress may be applied to the slider 706because of the movement of the guide rail 705 along with the annualplates of the shape-control devices 704. The slider 706 may slide fromthe bottom 707 to the top 708 of the guide rail 705 upon the stress. Theslit-plate 709, which is connected to the slider 706, may be driven todifferent locations in a radial direction of the annual plates of theshape-control devices 704. During this process, the FOV as well as theshape formed by the slit-plates may be changed (e.g., be enlarged).

When the slider 706 is moved to a certain location, for example, thelocation 711 as illustrated in FIG. 7B, the whole-body scanning mode maybe initiated. The FOV may be oval in the whole-body scanning mode, andthe slit-plates may form an oval shape as described with reference toFIG. 5B.

In some embodiments, the actuating device may drive the shape-controldevices 704, as well as the slit-plates of the collimator assembly 701,to move in the z-direction. In some embodiments, the number of slitsused in the scanning may be altered, and the scanner 700 may switchbetween the whole-body scanning mode and the heart scanning mode bymoving the shape-control devices 704 in the z-direction.

In some embodiments, the slit-plates, which extends in the z-direction,may be longer than the detector assembly 702. For example, the length ofthe slit-plates may be twice the length of the detector assembly 702 inthe z-direction. The slit-plate may include a plurality of segments inthe z-direction. At least one of the plurality of segments may include adifferent number of slits. For example, a first segment of theslit-plates corresponding to a range of z=0-10 in the referencecoordinate system 114 may include twenty slits, and a second segment ofthe slit-plates corresponding to another range of z=10˜20 may includeone hundred slits.

When the shape-control devices 704, as well as the slit-plates of thecollimator assembly 701, is moved to a certain location, for example, asillustrated in FIG. 7C, the heart scanning mode may be initiated. At thecertain location, a different segment with a different number of slitsmay be positioned above the detector assembly 702. The FOV may bechanged accordingly as described with reference to FIG. 5C and/or FIG.5D.

It should be noted that the above description of the scanner 700 ismerely provided for the purposes of illustration, and not intended tolimit the scope of the present disclosure. For persons having ordinaryskills in the art, multiple variations and modifications may be madeunder the teachings of the present disclosure. For example, theshape-control devices may be omitted, and the slit-plates may bedirectly driven to the certain locations (e.g., the locations shown inFIG. 5A through 5D, and/or the locations shown in FIG. 7A through 7C) bya plurality of actuating devices. However, those variations andmodifications do not depart from the scope of the present disclosure.

FIG. 8 is a schematic diagram illustrating a cross-sectional view of anexemplary scanner including a bore adjusting device according to someembodiments of the present disclosure. Similar to the embodiments shownin FIG. 6, the scanner 800 may include a collimator assembly 801, adetector assembly 802, and a control device 803. The control device 803may include a plurality of bore adjusting devices. The bore adjustingdevices may be used to adjust the diameter of the bore of the scanner800. In some embodiments, the diameter of the bore may be referred to asthe diameter of the shape form by the slit-plates of the collimatorassembly 801. Taking a bore adjusting device 804 as an example. The boreadjusting device 804 may be a plate includes a rigid rod and a junctionplate. The junction plate may connect to the slit-plate 805 and 806through joints 807 and 808 respectively.

The control device 803 may further include an actuating device. Theactuating device may be coupled to the rigid rod to drive the rigid rodto move in the y-direction. In some embodiments, the rigid rod and theconjunction plate may be fixed together (e.g., by screws, adhesives,etc.). Thus, the slit-plates 805 and 806 may be driven, in radialdirections in x-y plane, by the control device 803 to farther locations.In some embodiments, when the diameter of the bore is increased, theshape formed by the four slit-plates may be broken and the slit-platesmay be separated from each other.

During the process of increasing the diameter of the bore of the scanner800, the sliders 809 and 810, which respectively connect to theslit-plates 805 and 806 through rigid plates, may be passively movedtoward the top of the guide rails. The bore may be at its largestdiameter when the sliders reach the top of the corresponding guiderails.

It should be noted that the above description of the scanner 800 ismerely provided for the purposes of illustration, and not intended tolimit the scope of the present disclosure. For persons having ordinaryskills in the art, multiple variations and modifications may be madeunder the teachings of the present disclosure. For example, the controldevice 803 may adjust the diameter of the bore by driving the boreadjusting device 804 to move in y-direction and driving theshape-control devices to do axial rotation in the meanwhile. However,those variations and modifications do not depart from the scope of thepresent disclosure.

Having thus described the basic concepts, it may be rather apparent tothose skilled in the art after reading this detailed disclosure that theforegoing detailed disclosure is intended to be presented by way ofexample only and is not limiting. Various alterations, improvements, andmodifications may occur and are intended to those skilled in the art,though not expressly stated herein. These alterations, improvements, andmodifications are intended to be suggested by this disclosure, and arewithin the spirit and scope of the exemplary embodiments of thisdisclosure.

Moreover, certain terminology has been used to describe embodiments ofthe present disclosure. For example, the terms “one embodiment,” “anembodiment,” and/or “some embodiments” mean that a particular feature,structure or characteristic described in connection with the embodimentis included in at least one embodiment of the present disclosure.Therefore, it is emphasized and should be appreciated that two or morereferences to “an embodiment” or “one embodiment” or “an alternativeembodiment” in various portions of this specification are notnecessarily all referring to the same embodiment. Furthermore, theparticular features, structures or characteristics may be combined assuitable in one or more embodiments of the present disclosure.

Further, it will be appreciated by one skilled in the art, aspects ofthe present disclosure may be illustrated and described herein in any ofa number of patentable classes or context including any new and usefulprocess, machine, manufacture, or composition of matter, or any new anduseful improvement thereof. Accordingly, aspects of the presentdisclosure may be implemented entirely hardware, entirely software(including firmware, resident software, micro-code, etc.) or combiningsoftware and hardware implementation that may all generally be referredto herein as a “block,” “module,” “module,” “unit,” “component,” or“system.” Furthermore, aspects of the present disclosure may take theform of a computer program product embodied in one or more computerreadable media having computer readable program code embodied thereon.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including electro-magnetic, optical, or thelike, or any suitable combination thereof. A computer readable signalmedium may be any computer readable medium that is not a computerreadable storage medium and that may communicate, propagate, ortransport a program for use by or in connection with an instructionexecution system, apparatus, or device. Program code embodied on acomputer readable signal medium may be transmitted using any appropriatemedium, including wireless, wireline, optical fiber cable, RF, or thelike, or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent disclosure may be written in any combination of one or moreprogramming languages, including an object-oriented programming languagesuch as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C #, VB.NET, Python or the like, conventional procedural programming languages,such as the “C” programming language, Visual Basic, Fortran 2003, Perl,COBOL 2002, PHP, ABAP, dynamic programming languages such as Python,Ruby and Groovy, or other programming languages. The program code mayexecute entirely on the user's computer, partly on the user's computer,as a stand-alone software package, partly on the user's computer andpartly on a remote computer or entirely on the remote computer orserver. In the latter scenario, the remote computer may be connected tothe user's computer through any type of network, including a local areanetwork (LAN) or a wide area network (WAN), or the connection may bemade to an external computer (for example, through the Internet using anInternet Service Provider) or in a cloud computing environment oroffered as a service such as a Software as a Service (SaaS).

Furthermore, the recited order of processing elements or sequences, orthe use of numbers, letters, or other designations therefore, is notintended to limit the claimed processes and methods to any order exceptas may be specified in the claims. Although the above disclosurediscusses through various examples what is currently considered to be avariety of useful embodiments of the disclosure, it is to be understoodthat such detail is solely for that purpose, and that the appendedclaims are not limited to the disclosed embodiments, but, on thecontrary, are intended to cover modifications and equivalentarrangements that are within the spirit and scope of the disclosedembodiments. For example, although the implementation of variouscomponents described above may be embodied in a hardware device, it mayalso be implemented as a software only solution—e.g., an installation onan existing server or mobile device.

Similarly, it should be appreciated that in the foregoing description ofembodiments of the present disclosure, various features are sometimesgrouped together in a single embodiment, figure, or description thereoffor the purpose of streamlining the disclosure aiding in theunderstanding of one or more of the various inventive embodiments. Thismethod of disclosure, however, is not to be interpreted as reflecting anintention that the claimed subject matter requires more features thanare expressly recited in each claim. Rather, inventive embodiments liein less than all features of a single foregoing disclosed embodiment.

In some embodiments, the numbers expressing quantities, properties, andso forth, used to describe and claim certain embodiments of theapplication are to be understood as being modified in some instances bythe term “about,” “approximate,” or “substantially.” For example,“about,” “approximate,” or “substantially” may indicate ±20% variationof the value it describes, unless otherwise stated. Accordingly, in someembodiments, the numerical parameters set forth in the writtendescription and attached claims are approximations that may varydepending upon the desired properties sought to be obtained by aparticular embodiment. In some embodiments, the numerical parametersshould be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques. Notwithstandingthat the numerical ranges and parameters setting forth the broad scopeof some embodiments of the application are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspracticable.

Each of the patents, patent applications, publications of patentapplications, and other material, such as articles, books,specifications, publications, documents, things, and/or the like,referenced herein is hereby incorporated herein by this reference in itsentirety for all purposes, excepting any prosecution file historyassociated with same, any of same that is inconsistent with or inconflict with the present document, or any of same that may have alimiting affect as to the broadest scope of the claims now or laterassociated with the present document. By way of example, should there beany inconsistency or conflict between the description, definition,and/or the use of a term associated with any of the incorporatedmaterial and that associated with the present document, the description,definition, and/or the use of the term in the present document shallprevail.

In closing, it is to be understood that the embodiments of theapplication disclosed herein are illustrative of the principles of theembodiments of the application. Other modifications that may be employedmay be within the scope of the application. Thus, by way of example, butnot of limitation, alternative configurations of the embodiments of theapplication may be utilized in accordance with the teachings herein.Accordingly, embodiments of the present application are not limited tothat precisely as shown and described.

We claim:
 1. An imaging system, comprising: a collimator assemblyconfigured to collimate photons emitted from an imaged subject, thecollimator assembly comprising: a plurality of slit-plates, each of theplurality slit-plates including one or more slits configured tocollimate the photons in a first direction, wherein the plurality ofslit-plates includes a first number of slit-plates in a first segment inthe axial direction and a second number of slit-plates in a secondsegment in the axial direction, and wherein the first number isdifferent from the second number; and a plurality of slats parallel to atransverse plane of the imaging system; a detector assembly configuredto generate signals based on the collimated photons; and a controldevice configured to control at least one of the plurality ofslit-plates to be moved from a first location to a second location toswitch between different scanning modes and provide a plurality offields of view of the imaging system.
 2. The system of claim 1, whereinthe plurality of slit-plates and the plurality of slats are physicallyseparated.
 3. The system of claim 1, wherein the slit-plates are curvedplates including multiple axially oriented slits, and wherein the one ormore slits are perpendicular to the transverse plane of the imagingsystem.
 4. The system of claim 1, wherein the plurality of slats isplaced between the slit-plates and the detector assembly for collimatingthe photons in a second direction.
 5. The system of claim 4, wherein theslats are extended radially on a surface of the detector assembly. 6.The system of claim 1, wherein the plurality of fields of view comprisesa first field of view corresponding to a first scanning mode forscanning a first body part and a second field of view corresponding to asecond scanning mode for scanning a second body part.
 7. The system ofclaim 6, wherein the control device is configured to move at least oneof the slit-plates from a first location to a second location to switchbetween the first scanning mode and the second scanning mode.
 8. Thesystem of claim 7, wherein the control device comprises an annular plateconnected to the at least one of the slit-plates.
 9. The system of claim8, wherein, to control at least one of the slit-plates to be moved froma first location to a second location, the control device is configuredto control the annular plate to rotate around an axis of the annualplate from a first angle to a second angle.
 10. The system of claim 1,wherein the axial direction is perpendicular to the transverse plane ofthe imaging system.
 11. The system of claim 1, wherein the controldevice includes an actuating device, and wherein the control device isconfigured to place the one or more slit-plates in the plurality oflocations to provide the plurality of fields of view of the imagingsystem using the actuating device.
 12. The system of claim 1, whereinthe plurality of slit-plates forms a bore configured to accommodate theimaged subject, and wherein the system further comprises a boreadjusting device configured to adjust the diameter of the bore.
 13. Animaging system, comprising: a collimator assembly including: a pluralityof slit-plates, each of the plurality slit-plates including one or moreslits, wherein the plurality of slit-plates includes a first number ofslit-plates in a first segment in the axial direction and a secondnumber of slit-plates in a second segment in the axial direction, andwherein the first number is different from the second number; and aplurality of slats defining a number of channels between each two of theadjacent slats, the channels arranged nonparallel to the one or moreslits; a detector assembly placed outside of the collimator assembly;and one or more control devices configured to adjust relative positionsbetween the slit-plates and the detector assembly to obtain anadjustable field of view surrounded by the slit-plates.
 14. The systemof claim 13, wherein the channels are substantially perpendicular to theslits.
 15. The system of claim 13, wherein the slats are arranged in afixed manner with respect to the detector assembly, and wherein theslats are configured to be placed at a plurality of locations relativeto the detector assembly.
 16. The system of claim 13, wherein the one ormore control devices comprise two control devices located at oppositeends of the detector assembly.
 17. A method of adjusting collimatorassembly performance, comprising: moving axially at least one of aplurality of slit-plates of a collimator assembly or one of a pluralityof slats of the collimator assembly to concurrently adjust a size of afield of view (FOV) surrounded by the collimator assembly, wherein theplurality of slit-plates includes a first number of slit-plates in afirst segment in the axial direction and a second number of slit-platesin a second segment in the axial direction, and wherein the first numberis different from the second number; wherein a detector assembly isplaced outside of the collimator assembly, wherein each of the pluralityof slit-plates includes one or more slits; wherein the plurality ofslats defines a number of channels between each two of the adjacentslats, and wherein the channels are arranged non-parallel to the one ormore slits.
 18. The method of claim 17, wherein moving axially at leastone of the plurality of slit-plates of the collimator assembly or one ofthe plurality of slats of the collimator assembly comprises rotating atleast one of a plurality of slit-plates or one of a plurality of slats.19. The method of claim 17, further comprising: forming the collimatorassembly with at least one opening from the plurality of slit-platesarranged in a ring configuration to form the opening.